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    <title>Tests for stereopsis</title>
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    <h2>Tests for stereopsis</h2>
        <p>
            Stereopsis is hightest, third step of binocular vision.
            It's process of perceiving depth by analizing images perceived by eyes from slighty different directions.
        </p>
        <p>
            To test stereopsis identical images are presented for left and right eye.
            Images differ each other with presentation direction.
            If patient can't see 3-dimensional object, he/she don't have ability to stereopsis.
        </p>
        <p>
            Program includes 5 test checking stereopsis.
            They consists of 2 identical elements presented from different directions:
                <ul>
                    <li>circles,</li>
                    <li>bucket,</li>
                    <li>eyes,</li>
                    <li>pick-a-stick,</li>
                    <li>figures.</li>
                </ul>
        </p>
        <p>
            Exemplary on picture 1 there is element visible for one eye and on picture 2 - visible for second eye.
            Pacient with ability to stereopsis should perceive this images like 3-dimensional.
        </p>

        <p>
            Patient can correct his phoria by moving one of elements in whichever direction.
            <ul>
                <li>up by pressing key &uarr;</li>
                <li>down by pressing key &darr;</li>
                <li>left by pressing key &larr;</li>
                <li>right by pressing key &rarr;</li>
            </ul>
        </p>

        <p>
            Phoria is calculated from following equation on the basics of movement suitable element <i>x</i> and distance from monitor <i>l</i>.
            <center>
                <img src="../../images/eqnPhoria.png" />
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        </p>

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            <img src="../../images/testStereopsisA.png" />
            <br/>
            <i>Image 1. Stereopsis test - image for first eye</i>
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        <br><br><br>
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            <img src="../../images/testStereopsisB.png" />
            <br/>
            <i>Image 2. Stereopsis test - image for second eye</i>
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